Otherness Analysis Of Chilling Stress On Chlorophyll Fluoresence Knetics Of Mutational E.grandis×E.urophylla

This expriment which for openning up the new ways of variety breeding on E.grandis×E.urophylla and offering theoretical principle and technology-support for the breeding technique of E.grandis×E.urophylla induced the seedings with PYM, EMS and NaN₃ in their half-death concentrations.And then breeded the survival seedings one by one as strains.Analyzed the chlorophyll fluoresence knetics of each strains after-2℃,-4℃,-6℃chilling stress for the resistive breeding of E.grandis×E.urophylla.The main results were as follow:1.After -2℃chilling stress,all the indexs of chlorophyll fluoresence knetics except Fo had a distinct differences between different strains.Most of strains could recover to the level of which had not been chilling sterssed rapidly and all of the curve became smoothly in the process of recovering.That was showed that,-2℃chilling stress could damage the seedings to a certain extant but the damage could be restore soon probable.2.The ranges of the indexs of chlorophyll fluoresence knetics for every strains were large indeed after-4℃chilling stress than -2℃.Some of strains could recover to the level of which had not been chilling sterssed rapidly but the other could not.That showed that,-2℃chilling stress brought different influences to different strains,some strains were reversible but other were not.3.After -6℃chilling stress,all the indexs of chlorophyll fluoresence knetics of all the strains except NO.155 had declined sharply and could not recover.It was revealed that,the damages all strains had been suffered except NO.155 from -6℃chilling stress were inreversible.4.The indexs of chlorophyll fluoresence knetics of NO.155 were excellent in all levels of chilling stress especially after -6℃chilling stress when all the other strains could not recover in the process of recovering.That showed that NO.155 strain was affected trivial.So it possible to be happened that the NO.155 was had a variation which could control its self-cold resistance.5.An appropriate selection level was very important to the resistive breeding. In this experiment,the influences -2℃chilling stress brought to were not strong enough so that was impossible to complete the selection,the influences -4℃chilling stress brought to were effectively that it was objective to select the strains which better than CK1 in cold resistance.-6℃chilling stress brought a badly damage that all the strains except NO.155 could not recovered so if made the selection in -6℃chilling stress,it was probably selected a mutant which improve its resistance evident.So the -4～-6℃chilling stress could be the selection level for this experiment.